Method and system for buffer state based low power operation in a moca network

ABSTRACT

A first device of a Multimedia Over Coax Alliance (MoCA) network may communicate with a second device of the MoCA network to control power-save operation of the second MoCA device. The first device may control the power-save operation of the second MoCA device based on an amount of data stored in a buffer, wherein the data stored in the buffer is destined for the second device. The buffer may be in a third device which sends the data to the second device, and/or the buffer may be in the first device. The first device may be operable to buffer data destined for the second device while the second device is in a power-saving state.

PRIORITY CLAIM

This patent application is a continuation of U.S. patent applicationSer. No. 13/328,634 filed on Dec. 16, 2011 now patented as U.S. Pat. No.8,788,728.

The above application is hereby incorporated herein by reference in itsentirety.

FIELD OF THE INVENTION

Certain embodiments of the invention relate to networking. Morespecifically, certain embodiments of the invention relate to bufferstate based low-power operation in a MoCA network.

BACKGROUND OF THE INVENTION

Existing in-home networks consume too much power. Further limitationsand disadvantages of conventional and traditional approaches will becomeapparent to one of skill in the art, through comparison of such systemswith some aspects of the present invention as set forth in the remainderof the present application with reference to the drawings.

BRIEF SUMMARY OF THE INVENTION

A system and/or method is provided for buffer state based low-poweroperation in a MoCA network, substantially as illustrated by and/ordescribed in connection with at least one of the figures, as set forthmore completely in the claims.

These and other advantages, aspects and novel features of the presentinvention, as well as details of an illustrated embodiment thereof, willbe more fully understood from the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an exemplary in-home network.

FIG. 2 depicts an exemplary networking device.

FIG. 3 is a diagram illustrating a network device transitioning into andout of a power-saving state.

FIGS. 4A and 4B depict controlling a state of operation of a networkdevice based on buffer levels.

FIG. 5 depicts buffering data in a proxy to support a power-saving stateof operation.

DETAILED DESCRIPTION OF THE INVENTION

As utilized herein the terms “circuits” and “circuitry” refer tophysical electronic components (i.e. hardware) and any software and/orfirmware (“code”) which may configure the hardware, be executed by thehardware, and or otherwise be associated with the hardware. As utilizedherein, “and/or” means any one or more of the items in the list joinedby “and/or”. As an example, “x and/or y” means any element of thethree-element set {(x), (y), (x, y)}. As another example, “x, y, and/orz” means any element of the seven-element set {(x), (y), (z), (x, y),(x, z), (y, z), (x, y, z)}. As utilized herein, the terms “block” and“module” refer to functions than can be implemented in hardware,software, firmware, or any combination of one or more thereof. Asutilized herein, the term “exemplary” means serving as a non-limitingexample, instance, or illustration. As utilized herein, the terms “e.g.”and “for example” introduce a list of one or more non-limiting examples,instances, or illustrations.

FIG. 1 depicts an exemplary in-home network. FIG. 1 illustrates a localarea network (LAN) 100 comprising network devices 102 and 104 a-104 ccoupled via a shared channel 106. The LAN 100 also comprises devices 110a and 110 b coupled to network devices 104 a and 104 c via links 112 aand 112 b, respectively.

The shared channel 106 may comprise, for example, wired and/or opticalcabling. In an exemplary embodiment, the shared channel 106 may comprisecoaxial cabling.

The device 102 may comprise circuitry operable to communicate over theshared channel 106. The circuitry of the device 102 may also be operableto support one or more of the devices 104 a-104 c operating in one ormore power-saving states, and/or the device 102 itself operating in oneor more power-saving states. The device 102 may be, for example, aset-top box, a gateway, or a router. In an exemplary embodiment, thedevice 102 may communicate over the shared channel 106 in accordancewith Multimedia over Coax Alliance (MoCA) standards. In such anembodiment, the device 102 may function as the network coordinator ofthe MoCA network.

Each of the devices 104 a-104 c may comprise circuitry operable tocommunicate over the shared channel 106. Where the network 100 is a MoCAnetwork, the devices 104 a and 104 c may be termed an “intermediatedevice” and the device 104 b may be termed a “terminal device.” Thedevice 104 c may be, for example, a wireless access point operable toconvert between the network protocols (e.g., MoCA or DOCSIS) utilized onthe shared channel 106 and the network protocols (e.g., IEEE 802.11)utilized on the link 112 b. The device 104 a may be, for example, anetwork adaptor operable to convert between the network protocols (e.g.,MoCA or DOCSIS) utilized on the shared channel 106 and the networkprotocols (e.g., HDMI or USB) utilized on the link 112 a.

The devices 110 a and 110 b may comprise circuitry operable tocommunicate media and/or data via the links 112 a and 112 b,respectively. Each of the devices 110 a and 110 b may be, for example,an end-point such as a television or personal computer.

In operation, communications on the shared channel 106 may becoordinated by the device 102. The device 102 may control which devicesare granted admission to the network 100. The device 102 may controlwhich of the devices of the network 100 may communicate on the sharedchannel 106, and control at which times and/or on which frequencies suchcommunication occurs. The device 102 may control whether one or moredevices of the network 100 are permitted to operate in a power-savingstate. When one or more devices of the network 100 are operating in apower-saving state, the device 102 may adjust its behavior and/or thebehavior of other devices, as is described in further detail below.

FIG. 2 depicts an exemplary networking device. The exemplary device 200comprises a plurality of modules including a digital signal processor(DSP) 202, a central processing unit (CPU) 204, a memory 206, and ananalog front end (AFE) 208. The device 200 may, for example, representany of the devices 102, 104 a, 104 b, and 104 c, although any one ofthose devices may comprise additional or fewer features than the device200.

The AFE 208 may be operable to transmit and/or receive informationutilizing any suitable communication protocol(s). The AFE 208 may beoperable to perform analog-domain processing operations that enabletransmission and/or reception of signals in accordance with one or morecommunication protocols. In an exemplary embodiment, the AFE 208 may beoperable to transmit and/or receive signals in accordance with MoCAstandards via a link 210, in accordance with another local areanetworking standard (e.g., Ethernet or Wi-Fi) via a link 212, and/or inaccordance with a point-to-point communication protocol (e.g., USB orHDMI) via a link 214. The AFE 208 may comprise, for example, one or moreclocks, one or more digital-to-analog converters, one or moreanalog-to-digital converters, one or more modulators, one or moredemodulators, one or more amplifiers, and/or one or more filters. In anexemplary embodiment, the AFE 208 may be configurable into variousstates of operation, with the different states of operation beingcharacterized by different power consumption. For example, in apower-saving state of operation, one or more clocks may be slowed downor shut off, one or more modulators and/or demodulators may beconfigured to utilize lower-order modulation, one or more amplifiers maybe configured to provide less gain, etc.

The CPU 204 may be operable to execute instructions (e.g., an operatingsystem) to control operations of the device 200. For example, the CPU204 may generate control signals for configuring a state of operation ofthe device 200, and controlling operation of the other components of thedevice 200. In an exemplary embodiment, the CPU 204 may be configurableinto various states of operation, with the different states of operationbeing characterized by different power consumption. For example, in apower-saving state of operation, the CPU 204 may execute fewerinstructions per time interval than when not operating in thepower-saving state.

The memory 206 may comprise any suitable type of volatile and/ornon-volatile memory operable to store data and/or instructions. Forexample, the memory 206 may be utilized to store instructions executedby the CPU 204 and buffer data being transmitted and/or received via theAFE 208.

The DSP 202 may be operable to perform digital signal processingalgorithms and functions in accordance with one or more communicationstandards. For example, the DSP 202 may be operable to perform digitalfiltering, constellation mapping, constellation demapping, interleaving,deinterleaving, and error correction. In an exemplary embodiment of theinvention, the DSP 202 may be operable to perform digital-domainprocessing functions that enable transmission and/or reception of datain accordance with various standards, such as MoCA, Ethernet, and/orHDMI, via the AFE 208. In an exemplary embodiment, the DSP 202 may beconfigurable into various states of operation, with the different statesof operation being characterized by different power consumption. Forexample, in a power-saving state of operation, differenterror-correction algorithms may be utilized, different interleaver depthmay be utilized, and different constellation mappings may be utilized.

FIG. 3 is a diagram illustrating a network device transitioning into andout of a power-saving state. Note that a single power-saving state isshown and discussed for clarity, but it should be recognized that aplurality of alternative power-saving states may be utilized, eachhaving different respective characteristics, non-limiting examples ofwhich will be presented below. Shown in FIG. 3 are the devices 104 a,102, and 104 c, with logical links between them represented as arrows302 and 304, the width of the arrows 302 and 304 representing thebandwidth of the logical links.

During time interval T1, the network coordinator 102 exchanges messages306 and 308 with the device 104 c and messages 310 and 312 with theother devices of the network (of which only device 104 a is shown forclarity of illustration) to coordinate the transition of device 104 cinto a power-saving state. The messages 306 may include a request forpermission to enter the power-saving state. In addition, the messages306, 308, 310, and 312 may include messages to coordinate variousparameters such that the transition of device 104 c to a power-savingstate does not cause lost data, intolerable latency, and/or otherproblems in the network. For example, the devices 102 and 104 a-104 cmay exchange parameters indicating (1) how long the device 104 c willremain in the power-saving state, (2) what messages the device 104 cwill listen to while in the power-saving state, (3) what messages thedevice 104 c will respond to while in the power-saving state, (4) whatsignal characteristics the device 104 c will detect while in thepower-saving state, (5) conditions for bringing the device 104 c out ofthe power-saving state before the predetermined duration has expired,(6) whether the device 104 c will be granted transmission opportunitieswhile it is in the power-saving state, (7) how long such transmitopportunities will last, (8) when such transmission opportunities willoccur, and/or (9) what PHY profile(s) will be used for communicationsbetween the device 102 and 104 c both during and after the time periodthat the device 104 c operates in the power-saving state. A PHY profilecould include parameters such as, for example, modulation profile (i.e.,the type and/or order of modulation to be used for each of one or moresubcarriers), preamble type, cyclic prefix length, and transmit power.For example, a device could utilize BPSK when operating in apower-saving state and 64, 128, or 256-QAM when not operating in apower-saving state.

During time interval T2, after completing coordination of thetransition, the device 102 may send a message 314 to device 104 cgranting permission for the device 104 c to enter the power-savingstate. Such a message may, for example, comprise information describingcharacteristics of the power-saving state (or set of power-savingstates). For example, such a message may comprise information of any ofthe characteristics described above (e.g., of sleep duration,functionality maintained during sleep operation, modulationcharacteristics, message exchange sequences to follow, wake triggers,etc.). In an exemplary scenario, the device 102 may consider sleepoperation parameters proposed by the device 104 c during time intervalT1, agreeing to such parameters and mandating and/or proposingalternative parameters as necessary. For example, during time intervalT1, the device 104 c might have proposed a sleep duration of S₁, whichis greater than device 102 will allow (e.g., under current systemconditions or ever). In such a scenario, during time interval T2, device102 may command a different sleep duration of S₂, which is acceptable todevice 102. Note that device 102 may determine sleep state parameters onits own or may, for example, determine sleep parameters based oncommunication with other devices in the network.

During time interval T3, the device 104 c may operate in thepower-saving state. In an exemplary embodiment, some bandwidth may bereserved for the device 104 c while it is operating in the power-savingstate. Such reserved bandwidth may be utilized by “always-on” portionsof the device 104 c and/or always-on devices which connect to thenetwork 100 via the link 112 b (FIG. 1). For example, a reservedbandwidth may be utilized for communication of time synchronizationinformation, interrupt signals, emergency signals, fault signals,wake-up signals, key network management control messages, etc.

While the device 104 c is in the power-saving state, other devices maybuffer traffic to be sent to the device 104 c. In an exemplaryembodiment, when the amount of buffered traffic waiting to be sent todevice 104 c reaches a threshold (e.g., a non-zero threshold), thedevice 104 c may be taken out of the power-saving mode and the trafficmay then be sent.

In an exemplary embodiment, higher layers (e.g., OSI layers 3 and above)of the device 104 c may remain on while the device 104 c is in thepower-saving state. Traffic generated by the higher layers may bebuffered while the lower OSI layers are in the power-saving state, andmay be transmitted upon the lower OSI layers coming out of thepower-saving state. In such a scenario, various inter-layer signalingfeatures may be incorporated at the interface between OSI layers, wheresuch signaling features concern the communication of power-save stateinformation. Such power-save state information (e.g., sleep duration,latency estimates, etc.) may, for example, be useful for the upperlayers when determining whether frame delays are the result ofcommunication error or by increased latency at a lower layer operatingin a power-save mode.

During time interval T4, the device 104 c may transition out of thepower-saving state and return to an active state in which it fullyparticipates in network activities. In an exemplary embodiment, thedevice 104 c may transition out of the power-saving state upon thedevice 102 signaling it to transition out of the power-saving state(e.g., because another device has latency-sensitive traffic to send tothe device 104 c). In an exemplary scenario, the device 102 may (e.g.,via signaling) know the identity of particular other network devicesthat presently have traffic buffered for the device 104 c. In such ascenario, the device 102 may signal such other devices (e.g., viabroadcast message, multicast message, and/or unicast messages) to notifysuch other devices that the device 104 c is active. Also for example,the device 104 c may signal other devices on the network (e.g., viabroadcast message, multicast message, and/or unicast messages) to notifysuch other devices that the device 104 c is active. In variousimplementations, other devices on the network that are not involved withthe communication of buffered traffic to the now-active device 104 c,may refrain from the communication of relatively low-priority trafficfor a particular period of time. Such operation may, for example, freeup bandwidth, particularly in contention-based medium access systems. Inother implementations, for example, the device 102 may be acting as anetwork coordinator, thus having control over bandwidth allocation onthe network. In such an implementation, the device 102 may allocatebandwidth relatively generously for communication with the now-activedevice 104 c, while allocating relatively low amounts of bandwidth forother communications, in particular when such communications have arelatively low priority.

FIGS. 4A and 4B depict controlling a state of operation of a networkdevice based on buffer levels. Referring to FIG. 4A, during timeinterval T1, the device 104 a is sending traffic to device 104 c.Subsequently, during time interval T2, the devices 102, 104 a, and 104 cexchange some information to place the device 104 c into a power-savingstate. Many non-limiting examples of such information were discussedpreviously.

Then, during time interval T3, the device 104 a is buffering the traffic(e.g., all or most of the traffic) that is destined for 104 a. Forexample, as illustrated during time interval T3, the buffer in device104 a may contain traffic buffered for device 104 c, where the amount ofsuch traffic is non-zero yet below the threshold amount of traffic 402.Upon the buffered traffic reaching the threshold 402, the devices 102,104 a, and 104 c may exchange messages to transition the device 104 cout of the power-saving state.

The threshold 402 may be predetermined and/or determined dynamicallyduring operation of the MoCA network. The threshold 402 may depend on,for example, the latency sensitivity of the data, the priority of thedata relative to other traffic in the network, the priority of thedevice transmitting the data relative to other devices in the network,and/or the priority of the device for which the data is destined,relative to other devices in the network. The threshold 402 may also,for example, depend on the amount of capacity in the buffer beyond thethreshold (e.g., excess capacity in the buffer of device 104 a maywarrant a relatively higher threshold, providing other constraints aremet). Also for example, the threshold 402 may depend on the amount ofbandwidth presently available and/or anticipated to be available on thenetwork for the communication of buffered traffic (e.g., if availablebandwidth is relatively low, it might be necessary to begin draining thebuffer sooner than under normal bandwidth availability conditions).Additionally for example, the threshold 402 may depend on the conditionof device 104 c's power supply (e.g., a device running on limitedbattery power may warrant a relatively higher threshold and relativelylonger sleep duration relative to a device receiving power from thegrid).

Next, during time interval T5, the device 104 a may transmit thebuffered traffic to the device 104 c. Such transmission may be performedin any of a variety of manners. For example, as mentioned previously, inan exemplary scenario in which the device 102 controls utilization ofthe communication bandwidth, the device 102 may explicitly grant thenecessary communication bandwidth for the communication of bufferedtraffic from device 104 a to device 104 b. In another exemplaryscenario, for example a scenario in which access to communicationbandwidth is contention-based, the device 104 a may contend for accessto the necessary communication bandwidth and then utilize acquiredbandwidth for the communication of the buffered traffic to device 104 c.

Now referring to FIG. 4B, during time interval T6, the device 104 a maycontinue transmitting the buffered traffic and the buffer level mayfall. In an exemplary embodiment, as long as the amount of data to betransmitted to device 104 c is above a second threshold, the device 104c may be prevented from going into a power-saving state. For example,the device 104 a may keep the device 102 apprised of the status of thebuffer data, and the device 102 may deny requests from the device 104 cto enter the power-saving state until the buffer level drops below thethreshold 404. In another example, the device 104 a may keep thedestination device 104 c apprised on the status of the buffer data,causing the device 104 c (e.g., operating in accordance with anestablished power-save protocol) to remain in an active state.

Then, in time interval T7, the amount of traffic buffered in the device104 c falls below the second threshold 404. In response to the trafficfalling below the second threshold 404, the devices 102, 104 a, and 104c may exchange some messages to transition the device 104 c into thepower-saving state. Note that such a second threshold 404 (as with thethreshold 402) may be static or dynamic (e.g., being adjusted based onany or all of the conditions discussed previously with regard to thethreshold 402). Also note that such a second threshold 404 may be set tozero or a non-zero value (e.g., depending on real-time network and/ordevice conditions). As a non-limiting example, if there are presently noor relatively few devices contending for bandwidth, it may be prudent tocompletely empty the buffer. Alternatively for example, if there ispresently a relatively large amount of contention for networkcommunication bandwidth, the second threshold 404 may be maintained(e.g., at least temporarily) at a relatively high value to allow otherdevices a fair opportunity to communicate.

Subsequently, during time interval T8, the device 104 a may buffer datato be transmitted to the device 104 c. Then, during time interval T9,the amount of data buffered may reach the threshold 402. In response tothe amount of buffered data reaching the threshold 402, the devices 102,104 a, and 104 c may exchange messages to coordinate the device 104 cexiting the power-saving state. Next, during time interval T5, thedevice 104 a may transmit the buffered traffic to the device 104 c.

FIG. 5 depicts buffering data in a proxy to support a power-saving stateof operation. Referring to FIG. 5, there is shown the devices 104 a, 104c, and 102. During time interval T1 the devices 104 c and 102 areexchanging messages to coordinate the device 104 c going into apower-saving state. Note that communication may also occur with device104 a, though such communication is not illustrated. This coordinationmay include an exchange of parameters which enable the device 102 toreceive packets destined for device 104 c while device 104 c is in thepower-saving state. Many non-limiting examples of such parameters werepresented previously. Also for example, such parameter exchange mayinclude a negotiation between the device 104 c and the device 102regarding the manner (e.g., timing, amount, etc.) in which the device102 may store information destined for the device 104 c.

During time interval T2, the device may 104 a may be sending packetsdestined for device 104 c. In time interval T2, however, the device 104c is in a power-saving state in which it is not enabled to receivepackets (or, for example, particular types of packets or signals).Accordingly, the device 102 receives and buffers the packets destinedfor device 104 c. As mentioned above, such receiving and buffering mayoccur in accordance with parameters negotiated between the device 104 cand the device 102.

During time interval T3, the amount of traffic buffered in device 102may reach the threshold 502. In response to the amount of buffered datareaching the threshold 502, the devices 102, 104 a, and 104 c (or, forexample, just devices 102 and 104 c) may exchange messages to coordinatethe device 104 c coming out of the power-saving state. Next, during timeinterval T4, the device 102 may transmit the buffered traffic to thedevice 104 c.

Note that in such an exemplary scenario, the source device 104 a neednot even be aware of the operation of and interaction between the device102 and the device 104 a. In other words, the device 104 a maycommunicate to the device 104 c in a completely normal manner, not evenknowing that the device 104 c is operating in and out of a power-savestate. In such an exemplary scenario, though not illustrated in FIG. 5,the device 102 may communicate acknowledgement and other responsivemessages to the device 104 a on the behalf of the sleeping device 104 c.For example, upon the successful completion of error detection by thedevice 102 for a received packet that is ultimately destined for thedevice 104 c, the device 102 may send any required acknowledgementmessage to the device 104 a. Such messaging may, for example, keepdevice 104 a from timing out while waiting for an ACK message andbelieving that a communication error has occurred.

In another exemplary scenario, the device 104 a may be made aware of thebuffering by device 102. For example, in such a scenario, device 104 amay send packets directly to the device 102 (e.g., rather than havingthe device 102 intercept packets addressed to the device 104 c). In sucha scenario, the source device 104 a may either accept response messages(e.g., ACK messages) from the device 102 and/or may accept belatedresponse messages from the device 104 c upon buffered messages beingforwarded to the device 104 c.

In accordance with various aspects of the present invention, one or morecircuits for use in a first device (e.g., device 102) of a MultimediaOver Coax Alliance (MoCA) network may communicate with a second device(e.g., device 104 c) of the MoCA network to control a state of operation(e.g., one or more power-save states of operation) of the second MoCAdevice. The one or more circuits may control the state of operation ofthe second MoCA device based on an amount of data stored in a buffer,wherein the data stored in the buffer is destined for the second device.The buffer may be in a third device which sends the data to the seconddevice, and/or the buffer may be in the first device. The one or morecircuits may be operable to buffer data destined for the second devicewhile the second device is in a power-saving state. The one or morecircuits may be operable to control the state of operation of the secondMoCA device based on a comparison of the amount of data stored in thebuffer to one or more thresholds (e.g., thresholds 402 and 404,threshold 502, etc.).

The one or more thresholds may be based on a latency tolerance and/orpriority of the data. The one or more thresholds may be based on apriority of the second network device relative to other devices in theMoCA network. The one or more circuits may be operable to control thestate of operation of the second device such that the second deviceenters a power-saving state of operation upon the amount of data in thebuffer falling below a threshold. The one or more circuits may beoperable to prevent the second device from entering a power-saving stateof operation while the amount of data in the buffer is above athreshold. The one or more circuits may be operable to control the stateof operation of the second device such that second device comes out of apower-saving state of operation upon the amount of data in the bufferrising above a threshold.

Other embodiments of the invention may provide a non-transitory computerreadable medium and/or storage medium, and/or a non-transitory machinereadable medium and/or storage medium, having stored thereon, a machinecode and/or a computer program having at least one code sectionexecutable by a machine and/or a computer, thereby causing the machineand/or computer to perform the steps as described herein for bufferstate based low-power mode in a MoCA network.

Accordingly, the present invention may be realized in hardware,software, or a combination of hardware and software. The presentinvention may be realized in a centralized fashion in at least onecomputing system, or in a distributed fashion where different elementsare spread across several interconnected computing systems. Any kind ofcomputing system or other apparatus adapted for carrying out the methodsdescribed herein is suited. A typical combination of hardware andsoftware may be a general-purpose computing system with a program orother code that, when being loaded and executed, controls the computingsystem such that it carries out the methods described herein. Anothertypical implementation may comprise an application specific integratedcircuit or chip.

The present invention may also be embedded in a computer programproduct, which comprises all the features enabling the implementation ofthe methods described herein, and which when loaded in a computer systemis able to carry out these methods. Computer program in the presentcontext means any expression, in any language, code or notation, of aset of instructions intended to cause a system having an informationprocessing capability to perform a particular function either directlyor after either or both of the following: a) conversion to anotherlanguage, code or notation; b) reproduction in a different materialform.

While the present invention has been described with reference to certainembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the scope of the present invention. In addition, manymodifications may be made to adapt a particular situation or material tothe teachings of the present invention without departing from its scope.Therefore, it is intended that the present invention not be limited tothe particular embodiment disclosed, but that the present invention willinclude all embodiments falling within the scope of the appended claims.

1. A system comprising: one or more circuits for use in a networkcoordinator device of a Multimedia Over Coax Alliance (MoCA) network,said one or more circuits comprising an analog front end, one or moreprocessors, and memory and being operable to, at least: communicate, viasaid analog front end, with a plurality of client devices of said MoCAnetwork to control power-save operation of each of said client devices;and control, by said one or more processors, said power-save operationof each of said client device based on: an amount of data stored in abuffer in said memory, wherein said data stored in said buffer isdestined for a first one of said client devices; and a comparison ofsaid amount of data stored in said buffer to a non-zero threshold storedin said memory, wherein said threshold is based on a priority of saidfirst one of said client devices relative to one or more others of saidclient devices.
 2. The system of claim 1, wherein said buffer is in asecond one of said client devices which sends said data to said firstone of said client devices.
 3. The system of claim 1, wherein saidbuffer is in said network coordinator device.
 4. The system of claim 3,wherein said one or more circuits are operable to buffer said datadestined for said first one of said client devices while said first oneof said client devices is in a power-saving state.
 5. (canceled)
 6. Thesystem of claim 1, wherein said threshold is based on priority of saiddata.
 7. (canceled)
 8. (canceled)
 9. The system of claim 1, wherein saidone or more circuits are operable to notify a second one of said clientdevices as to times when said first one of said client devices will bein a power-saving state.
 10. The system of claim 9, wherein said one ormore circuits are operable to notify said second one of said clientdevices as to a first physical layer profile to use for communicationwith said first one of said client devices during said times when saidfirst one of said client devices is in said power-saving state, and asecond physical layer profile to use for communication with said firstone of said client devices during times when said first one of saidclient devices is not in said power-saving state.
 11. A methodcomprising: performing by one or more circuits in a network coordinatordevice of a Multimedia Over Coax Alliance (MoCA) network: communicatingwith a plurality of client devices of said MoCA network to controlpower-save operation of each of said client devices; and controllingsaid power-save operation of each of said client devices based on: anamount of data stored in a buffer, wherein said data stored in saidbuffer is destined for a first one of said client devices; and acomparison of said amount of data stored in said buffer to a non-zerothreshold, wherein said threshold is based on a priority of said firstone of said client devices relative to a one or more others of saidclient devices.
 12. The method of claim 11, wherein said buffer is in asecond one of said client devices which sends said data to said firstone of said client devices.
 13. The method of claim 11, wherein saidbuffer is in said network coordinator device.
 14. The method of claim13, comprising, performing by the one or more circuits of the firstdevice: buffering said data destined for said first one of said clientdevices while said first one of said client devices is in a power-savingstate.
 15. (canceled)
 16. The method of claim 11, wherein said thresholdis based on priority of said data.
 17. (canceled)
 18. (canceled)
 19. Themethod of claim 11, comprising notifying a second one of said clientdevices as to times when said first one of said client devices will bein a power saving state.
 20. The method of claim 19, comprisingnotifying said second one of said client devices as to a first physicallayer profile to use for communicating with said first one of saidclient devices during said times when said first one of said clientdevices is in said power-saving state, and a second physical layerprofile to use for communicating with said first one of said clientdevices during times when said first one of said client devices is notin said power-saving state.
 21. The system of claim 1, wherein saidthreshold is based on latency tolerance of said data.
 22. The method ofclaim 11, wherein said threshold is based on latency tolerance of saiddata.